Pharmacist says 'don't' as warning issued over vitamin D tabletsMillions of people are taking vitamin D supplements as advised by expertsView Image A woman getting her daily dose of vitaminsA pharmacist has issued a warning that millions of Brits could be taking their vitamin D tablets incorrectly, significantly reducing the effectiveness of these essential supplements. Across the UK, people have started taking vitamin D pills following advice from medical professionals and experts, including the late Michael Mosley. It's really common to take vitamin D supplements, especially as many of us will not get enough vitamin D from sunlight or food alone. "Don't take too much vitamin D. Because it's a fat soluble vitamin it can build up in your body easier than other vitamins. 4,000 IU or 100 mcg is considered to be the upper limit of safe vitamin D supplementation."